'You'll swear to that?'

'Certainly I will. But there's just one other thing.'

'What?'

'Why, one of the windows on the ground-floor--left of the door--is open.'

'Is it really so? My goodness! he must have got in,' said Williams, with
great excitement; and he hurried to the back of the sofa on which Nisbet
was sitting, and, catching the picture from him, verified the matter for
himself.

It was quite true. There was no figure, and there was the open window.
Williams, after a moment of speechless surprise, went to the
writing-table and scribbled for a short time. Then he brought two papers
to Nisbet, and asked him first to sign one--it was his own description of
the picture, which you have just heard--and then to read the other which
was Williams's statement written the night before.

'What can it all mean?' said Nisbet.

'Exactly,' said Williams. 'Well, one thing I must do--or three things,
now I think of it. I must find out from Garwood'--this was his last
night's visitor--'what he saw, and then I must get the thing photographed
before it goes further, and then I must find out what the place is.'

'I can do the photographing myself,' said Nisbet, 'and I will. But, you
know, it looks very much as if we were assisting at the working out of a